This invention is related to an apparatus for attaching resists and wafers to substrates which is mainly utilized for attaching a plurality of resists onto a surface of a wafer prior to a subsequent sand blasting operation. More particularly, the invention is utilized in the processes of producing circular semiconductor dice, nevertheless, it can be used in other technical fields in which attachment of different kinds of resists is required. The invention applies wax for adhering a wafer to a glass substrate as well as adhering a plurality of resists made of metal or plastic to the wafer. Sand blasting, resolution, separation and drying processes may be further conducted so as to form a number of individual circular semiconductor dice.
In the manufacture process of semiconductor device, the silicon ingot is generally sliced into flat circular wafers with a diameter of several inches or bigger after completing the growth of silicon crystal. For certain applications, the wafer 10, as illustrated in FIGS. 1 and 2, needs to be further machined so as to form small semiconductor dice for actual utilization.
One of the existing processes of forming small semiconductor dice is to manually adhere a plurality of resists 11 made of metal or plastic onto the wafer 10 as shown in FIG. 2 to cover and protect the areas of the semiconductor dice to be formed. Silicon carbide or other appropriate abrasive media are then used to blast and thus wear away the wafer at the areas without the cover of the resists 11 in order to form a number of individual flat circular semiconductor dice.
The conventional processes of attaching the resists to the wafer are completely conducted by hand and thus, are very inefficient, labor consuming, and can only be achieved by persons with proficient skills. A more detailed description of the conventional processes are substantially illustrated in FIG. 3 including the steps of: melting wax, usually a high-temperature wax, within a tank which can be maintained at a constant temperature; the operators then grip the wafer with tweezers and dip it into the tank so that both sides of the wafer are covered by the wax (step 100); placing the waxed wafer on a glass plate which has been preheated on a hot plate (step 110); the operators shake a tray with a plurality of resists therein and let the resists fall into a mold with a desired pattern, the arranged resists are then adhered onto a tape which is cut into pieces after the adhesion of the resists (step 105); placing the tape with resists thereon over a hot plate with the resists facing upwardly (step 115); placing the combination of the wafer and the glass plate from step 110 over the tape with resists thereon and letting the glass plate at the top (step 120); the operators rub the glass plate with a stick to squeeze out any possible air bubble existed within the wax between the wafer and the glass plate (step 130); and removing the combination of the glass plate, the wafer and the resists from the hot plate and peeling off the tape after the wax is cured (step 140). A sandwich combination as shown in FIG. 2 can thus be formed for subsequent sand blasting operation. The sandwich combination includes, from the top to the bottom, the resists 11, a first layer of wax 12, the wafer 10, a second layer of wax 14 and the glass plate 13.
Although the above technique can achieve the purpose of attaching the resists on the wafer, it still involves various disadvantages. Firstly, the entire operation is manually conducted by operators and therefore requires a lot of labor and the production expense thereof is quite high. Secondly, the conventional processes require proficient skills from the operators to limit the amount of the air bubbles within the wax between the wafer and the glass plate below certain value such that a satisfactory production yield of the final semiconductor dice may be achieved. In particular, the entire dependency on human operators of the conventional processes will result in both the quality and quantity of the products being greatly effected by the emotion, health, or other personal conditions and can hardly remain stable. In addition, the operation of high temperature wax by human operators needs to be improved in consideration of the safety and hygiene situations in the processes. Furthermore, the amount of wax applied by human operation cannot be constantly controlled and an extra amount of wax may be wasted accordingly. In general, the wax will be resolved by acetone in the subsequent processes and thus, if the amount of wax used for attaching the resists is reduced, it will require less amounts of acetone for resolution of wax and thus decrease the environmental pollution induced from the resist attachment operation.
It is therefore a primary object of this invention to overcome the above defects of conventional art and to provide an automatic apparatus for attaching resists and wafers to substrates, including: a plurality of substrates; a first magazine receiving the substrates; a first moving device which removes the substrates out of the first magazine; a plurality of wafers, each having a first side and a second side opposite to the first side; a second magazine receiving the wafers; a second moving device which removes the wafers out of the second magazine; a first tank for containing a first adhesive agent; a dispensing device which dispenses a predetermined amount of the first adhesive agent from the first tank to a substantially central region of the first side of each of the wafers; a third moving device which places each of the substrates on the first side of each of the wafers such that the substrate and the wafer are attached by the first adhesive agent to form a substrate-wafer unit; a compressing device which compresses each of the substrates to squeeze out any possible air bubbles existing within the first adhesive agent between each of the substrates and the wafers such that the first adhesive agent applied therebetween is of a uniform thickness; a second tank for containing a second adhesive agent; a fourth moving device which moves the substrate-wafer unit to the second tank such that the second side of each of the wafers is completely coated with the second adhesive agent; a mold having a plurality of cavities which have an amount substantially less than the resists and which are configured to a required pattern; a supplying device which supplies the resists on the mold; a shake-and-load device which shakes the mold such that each of the cavities receives one of the resists; an adherent tape adhering the resists received in the cavities onto the tape to form a resist-tape unit such that the required pattern of the resists is presented on the tape; the fourth moving device which moves the second side of the wafer coated with the second adhesive agent to be attached to the resists thereby the substrate-wafer unit is attached to the resist-tape unit; and a wrapping device which moves the adherent tape to separate the adherent tape from the resists adhered thereonto, thereby forming a plurality of layered sandwich combinations each sequentially including the patterned resists, the second adhesive agent, the wafer, the first adhesive agent, and the substrate.
One of the primary features of this invention resides in that this invention can overcome all the disadvantages induced from the conventional manual operation. Automation of the complete resist attachment process can not only save enormous labor expense and lower the costs of the process, but also significantly improves the efficiency and shortens the required time of the process.
Another feature of this invention resides in that, the automation of the complete process of this invention may further ensure the stability of the product such that the quality and quantity of the resist attachment process can remain consistent and will not be affected by personal emotion or health conditions.
A further advantage of this invention is that the safety and hygiene of the resist attachment process can be improved by avoiding direct contact of the operators with the high temperature wax. Additionally, the apparatus of this invention can decrease the amount of wax needed for attaching the resists and thus reduce the amount of acetone required in the subsequent resolution process and decrease the environmental pollution induced therefrom.